I can't answer your first question about the toxins, but in answer to your second one about the juices: it was my experience that it's alright to use a juice you prefer. Some people apparently swear by lemon and others by grapefruit -- and always fresh-squeezed, but the one time I did Clark's flush, I used what I had on hand, which was orange-pineapple juice from a carton. This was several years ago, and as I recall, I got out somewhere around 100 "stones" over several bowel movements -- the size, color, and consistency of baby peas. (I happen to be reading this forum today because, thanks to increasingly worse gallstone symptoms, I'm having to do another long-overdue flush today.) I hope this helps.